Why Can't I Extend a C Drive With Free Space? How to Fix It?

It's troublesome that I have enough free space on my hard drive, but I can't use them to increase the size of my C drive. I tried Disk Management, and the extend volume option is greyed out. I want to know why this is happening and How I can fix this issue.

Best Answered by

Roxanne· Answered on Feb 21, 2024

Have you ever encountered an "Extend Volume greyed out and can't extend partition" problem? In this post, I will explain why this would happen and teach you how to deal with it. Check out and learn the solution to enable the C drive extension now. Regarding the reason why you can't extend the C drive even with free space, I will discuss the following primary causes:

  • The C drive is locked by another process or application, leaving you unable to resize the system partition.
  • The unallocated or free space is not behind the C drive you intend to extend. 

Now that we know why you can't resize the C drive with free space. For the first reason, you'd better close all running programs before conducting any actions on the C drive. And for the second reason, you need to turn to a professional and free partition tool EaseUS Partition Master. It can offer two practical tools that enable you to extend the C drive without adjacent unallocated space smoothly and quickly. In addition, this software is operable even if you are a computer beginner.

Free Download 

Windows 11/10/8/7100% Secure

Solution 1. Allocate Space

This feature will extend your C drive by allocating space from other partitions. You can learn how to use it below:

Step 1. Right-click on the partition with enough free space and choose "Allocate Space."

Step 2. Select the C drive (System partition) and drag the partition end to allocate free space from another partition to the C drive. Then click "OK."

Step 3. Click "Execute Task" > "Apply" to start allocating.

Solution 2. Adjust with 1-Click

If your C drive is full and receives a warning message for low disk space, "Adjust with 1-Click" of EaseUS Partition Master would be your best solution. Here is the complete guide on extending the C drive with "Adjust with 1-Click":

Step 1. Launch EaseUS Partition Master, which shows a low space alert in the interface. Select "Adjust with 1-Click" and click "OK" to confirm.

(You can also adjust the space using the "Manual Adjustment" option: drag the end of the C drive rightward to add free space.)

Step 2. Select the "Execute 1 Task" option and hit "Apply" to end the extending process.

If you only have one partition(C drive) on your hard drive, you can explore the method for extending the C drive from another disk in the following article:

Related Article: How to Extend C Drive from Another Disk in Windows 10/11?

People Also Ask

How to Move Recovery Partition

Have you encountered the Extend Volume option greyed out in Disk Management? Is there a recovery partition between the partition you want to extend and unallocated space? If so, check this page, and you will find the solution to this issue.


Jan 25, 2024

Can You Move C Drive to New Disk?

If your C drive is out of space and you want to replace the disk with a larger one, can you move C drive to new disk? Continue reading on this page, and you'll get the answer.


Jan 05, 2024

How Many Partitions Can Be Made in a Hard Drive in Windows?

Many users are planning to create partitions on their hard drives. Then how many partitions can be made in a hard drive in Windows? This article contains everything you want about the maximum number of partitions on the hard drive.


Jan 05, 2024

Is It Possible to Partition My Hard Drive Before Installing Windows?

Is it possible to partition my hard drive before installing Windows? This page will give you answers and teach you how to partition your hard drive before Windows installation.


Jan 05, 2024

What Should I Do to Shrink Three Partitions Into Two?

If you want to shrink three partitions into two without data loss, refer to this passage containing an applicable method.


Jan 05, 2024

What Is the Difference Between Primary Partition and Basic Data Partition?

What is the difference between primary Partition and basic data partition? If you are intrigued by this question, continue to read and learn all the information you need.


Jan 05, 2024